Van der Waals interactions from the exchange hole dipole moment: Application to bio-organic benchmark systems

We have recently completed the development of a simple model of the dispersion interaction based on the dipole moment of the exchange hole [E.R. Johnson, A.D. Becke, J. Chem. Phys. 124 (2006) 174104, and references therein]. The model generates remarkably accurate dispersion coefficients, geometries, and binding energies of intermolecular complexes. In this work, the model is tested on three biochemical benchmark systems: binding energies of nucleobase pairs, relative conformational energies of the alanine dipeptide, and the anomeric effect from conformational energies of substituted tetrahydropyrans and cyclohexanes. The model gives binding energies and conformational energies in good agreement with correlated ab initio reference data.